Large area x-ray detector

This is an x-ray detector built by [Ben Krasnow]. It’s an interesting combination of parts working with an oscilloscope. The result is an audible clicking much the same as you would hear from a Geiger counter

He’s measuring backscatter, which is the reflection of x-rays on other objects. Because the signal will be quite weak compared to waves emitted directly from an x-ray source he needed a large collector to measure them. He started by gutting an x-ray image intensifying cassette. This has a phosphor layer that glows when excited by x-rays. The idea is that the glowing phosphors do a better job of exposing film than direct x-rays can. But [Ben’s] not using film. He built that pyramid-shaped collector with the phosphor material as the base. At the apex of the pyramid he mounted a photomultiplier tube (repurposed from his scanning electron microscope) which can detect the excited points on its surface. His oscilloscope monitors the PMT, then issues a voltage spike on the calibration connector which is being fed to an audio amplifier. Don’t miss his presentation embedded after the break.

[Ben] mentions that this build is in preparation for a future project. We’d love to hear what you think he’s working on. Leave your guess in the comments section.

I sure didn’t see this coming… nice clean, sharp interface, but, uhh… this is going to take me a while to adjust to.
I guess forgoing any announcements of impending change is one way to avoid a preemptive crapstorm….

also, for some reason, it *really* hurst my eyes. Not in a sarcastic “10,000 razorblades sort of way”, but literally. I don’t know how else to describe it. It hurts to look at the new page design. I hope that’s only temporary.

Uhh, hurts. Not hurst. Derp. Sure would be nice to have an edit button for comments…

And I still have a missing cursor line… if I want to click back into something I’ve already typed, I have to click where I want to go and then hope that I’ve clicked properly. Until I type and see letters appear, I have no indicator of where the cursor is… this has been going on for quite some time (and only on HAD, fwiw), and the new update hasn’t changed that odd behaviour.